When the satellite Cosmos 2519 was launched
into space by Russia last year, the world did not know why.
Now, a US diplomat warned a global
arms control conference in Geneva on Aug. 14 that “we are
concerned with what appears to be very abnormal behavior by a
declared ‘space apparatus inspector.’ We don’t know for
certain what it is, and there is no way to verify it.”

The official statement from Yleem Poblete, the top
US diplomat on arms control issues,
suggests American intelligence agencies have reason to believe
the satellite may be surveilling US
space assets—or practicing to attack them in the future.

After launch, Cosmos 2519 deployed
two smaller satellites, and maneuvered to rendezvous with
them. Because bringing propellant to space is difficult, most
satellites are designed to fly to a designated orbit and then
make small adjustments to their position. A satellite that can
travel between orbits to check in on other satellites is
relatively unusual.

Such a vehicle could be used for many purposes: To perform
maintenance on or re-fuel older satellites, extending their
lives, or to clean up space debris, even sending old
satellites to storage orbits or to burn up in the atmosphere.
It could also be used to spy on other satellites and attack
them with lasers, robotic manipulators or simply by crashing
into them.

The US military is certainly
tracking the Russian satellite’s position using ground-based
radar, but the ability to ascertain what it is doing is
limited. Powerful cameras at ground bases or on spy satellites
can zoom in on passing spacecraft only if its orbit aligns
with their field of view.

China and Russia have been performing more tests of “dual
use” space hardware that could be innocuous or a weapon.
Vladimir Putin announced a package of new weapons programs
earlier this year, including an anti-satellite laser. That
escalation is one reason why the US
is considering the creation
of a dedicated military force for space.

The US, of course, has its own
military capabilities in space. It tested an anti-satellite
missile in 2008, and regularly
operates the X-37B spacecraft, a miniature space shuttle
that can also maneuver in space and whose purpose is the
subject of much speculation.

Most valuable
space assets—constellations of huge navigation,
communications, surveillance and missile-detection
satellites—are protected largely because they are so far away
from Earth and orbiting quickly. As potential adversaries
demonstrate the ability to reach out and touch these, they are
far more vulnerable than they appeared just a few years ago.